As people, pets, and objects move from place to place, their feet or wheels often pick up dirt and debris, which is carried along as they move. The dirt and debris is thereby spread to other places, such as the interiors of houses, offices, and hospitals. Obviously, it is desirable to prevent the spread of dirt and debris, and many attempts have been made to do so. Chief among these are rugs and mats that are placed in the entryways of homes, offices, and hospitals. It is hoped that these rugs or mats will remove and retain some of the dirt and debris from the shoes and wheels of people, pets, and objects. However, this is often not the case. In many situations, these rugs and mats are not frequently or sufficiently cleaned and are themselves a source of dirt and debris. Also, even a clean rug or mat often does a poor job of removing dirt and debris from feet and wheels. These mats and rugs also preferably remove liquid from feet and wheels. However, they often do an insufficient job of this as well. They may have limited absorption and may also become quickly wetted where they no longer can absorb additional liquid.
The problem of dirt and debris on the shoes of people is especially worrisome in hospital operating rooms and manufacturing clean room facilities. For these purposes, “tacky mats” have been developed. These mats typically consist of a plurality of layers of thin plastic with adhesive coated on the upper surface of each layer. In theory, a person walks across the mat and the adhesive grabs the dirt and debris from the underside of their shoes. Once the mat is sufficiently covered with dirt and debris, the soiled layer is peeled from the remaining layers to expose a fresh layer with fresh adhesive. Examples of these types of mats are disclosed and explained in U.S. Pat. Nos. 4,107,811 to Imsande and 4,559,250 to Paige. While this type of mat may have limited applicability, it suffers from numerous shortcomings. The plastic layers easily tear when removed and also require users to carefully walk across them to avoid tearing in use. The adhesive on the layers only removes dirt and debris that is lightly attached to the underside of the shoes. If the shoes are more heavily soiled, it is impossible for the user to wipe their feet, since doing so would likely tear the plastic sheet. Probably the most serious drawback of this type of mats is that they are absolutely incapable of absorbing liquids from the bottom of shoes. Therefore, they are only suited for applications where it is known that the shoes are already dry. Hence, the mats cannot be used in entryways to buildings where shoes may be heavily soiled and/or wet.
A slight improvement is provided by a tacky mat disclosed and explained in U.S. Pat. No. 3,665,543 to Nappi. In this version, a gauze sheet is embedded in the adhesive layer and fully saturated with adhesive. The gauze sheet serves the dual purposes of strengthening the plastic underlayer and providing a rougher upper surface to improve retention of dirt and debris. However, this mat still fails to address the need to absorb liquids. It also is only suitable for very light wiping since the gauze layer is insubstantial.
A different approach to the mat or rug problem is taken by U.S. Pat. Nos. 5,506,040 and 5,834,104 to Cordani and U.S. Pat. No. 5,173,346 to Middleton. In each of these patents, an absorbent layer overlies a moisture barrier layer. The absorbent layer absorbs liquid and the moisture barrier layer prevents the liquid from transferring out of the mat. In the case of the Middleton patent, the absorbent mat is designed to catch and absorb fluids which drip from an operating table during surgery. Therefore, the absorbent layer is highly absorbent and retentive of fluid, but is not designed to be walked across as with a normal rug or mat used in an entryway. The Cordani patents disclose mats which are designed for use in entryways. Therefore, the absorbent layer is designed to be walked across and absorbs liquid and tolerates at least some wiping of shoes. However, the Cordani mats lack the tackiness of the previously discussed “tacky mats” and therefore have limited capability to grab dirt and debris from the shoes of people walking over the mat. Also, the Cordani mats are only a single layer and therefore lack the functionality of the plurality of sheets used in a typical tacky mat. A significant advantage to the stacked tacky mats is that users may very easily “clean” the mat by simply peeling off and disposing of the uppermost layer. With the Cordani mats, the entire mat must be replaced. This discourages “cleaning.”
In light of the above, there remains a need for a cleaning mat or rug which encourages users to “clean” the mat whenever the mat becomes soiled, is capable of tolerating wiping, absorbs liquids, and has the capability to grab and retain dirt and debris.